This project intends to isolate native fragments of bovine serum albumin (i.e., fragments obtainable without cleavage of disulfide bonds) by mild proteolytic digestion and to study their relationship to the structure of the parent molecule, their affinity for palmitate and bilirubin, and their interactions with each other. Likewise characterization of rat serum albumin will be conducted in a similar fashion, followed by studies of the structure of rat albumin "precursors" occurring in the secretory channels of rat liver.